SE530524C2 - Percussion, rock drilling machine including such percussion and method for controlling percussion - Google Patents

Abstract

A percussive device and method having, inside a machine housing (3), a reciprocally moveable percussive piston (2), the movement of which is controlled by a control valve (5), which is arranged to alternatively connect a chamber to a pressure source and to low pressure in dependence on a signal corresponding to the axial position of the percussive piston, and a valve (16) arranged to allow adjustment of the axial position of the percussive piston at which the signal is transmitted, by opening and blocking of a connection between one or more control channels (10, 11, 12, 13) and the control valve.

Description

10 15 20 25 30 530 524 a percussion instrument with simpler and safer control possibilities with regard to the movement of the percussion piston.

These objects are achieved according to the invention by the features of the characterizing part of claim 1.

In this way it is achieved that a distinct adjustment of the stroke length of the percussion piston is certainly made possible. This means a great advantage, since the possibility is offered that the stroke can be easily controlled by emitting only uncomplicated input (and possibly output) signals to the valve elements to vary the impact energy emitted from the percussion in response to the needs of the special work situations. This is in contrast to the prior art, in which a valve body is moved between several different axial positions for opening each of several axially spaced guide channels.

If you want to change the stroke position of a percussion instrument, you can move backwards, ie. in the direction from the drill neck, the adjustment channel (control channel) for high pressure, which results in a longer stroke and more force in each stroke. Given the same pressure, it takes longer to accelerate the piston as the stroke is longer, which results in drilling with a lower frequency.

In general, it can be said that there is a desire to vary the percussion energy of the percussion unit according to the hardness variation of the rock. In particular, control of the percussion instrument in this respect is desired according to the needs that exist in a current part of the rock. Through the invention, the percussion device can be controlled by simple means in the direction of optimizing the drilling and reducing shock wave reflections, which will not benefit the drilling process.

Generally for a drilling process, there are indications that drilling with a new drill bit takes place with too high impact energy.

This is due to the fact that with a new drill bit only a small part of the drill bit processing units come into actual engagement with the rock. After a certain wear of the drill bit, however, the impact energy will gradually be automatically adapted to the slightly worn shape of the drill bit engaging portions, whereby the efficiency of the drilling process will increase. With continued wear of the drill bit, however, the efficiency will fall again due to less good adaptation of the impact energy to the actual appearance of the bit.

The invention enables this phenomenon to be taken into account and the impact energy to be controlled in order to be better adapted to the wear condition of the drill bit. This entails the possibility of obtaining increased drilling subsidence at the same percussion effect, less stresses in the drill steel, less reflections from the rock, which in turn may mean that a smaller damping unit becomes necessary. Through the invention, a drilling machine can be easily adapted to varying crown wear, rock strength and crown size.

In this case, the drilling machine can be set in advance for some of the parameters, which are known, or can be regulated during drilling as required and sensed parameters.

In a preferred embodiment of the invention, the control is possible in response to a parameter describing the drilling process, such as for example the drilling subsidence or the pressure in a damping chamber or as a result of a shock wave amplitude sensed by shock wave measurement.

Additional advantages are achieved by further aspects of the invention, as will be apparent from the following description of an exemplary embodiment.

DESCRIPTION OF DRAWINGS The invention will now be described in more detail with reference to exemplary embodiments and with reference to the accompanying drawings, in which: Fig. 1 shows schematically, in an axial section, a part of a drilling machine including a percussion instrument according to the invention, Fig. 2 shows schematically, in an axial section, a valve member according to the invention at a percussion device, Fig. 3a - “d shows in section the valve member in Fig. 2 in different positions, Figs. 4a - d show in section another valve member according to the invention in different positions, and Pig. 5 illustrates a block diagram of a method to which the invention is applied.

DESCRIPTION OF EMBODIMENTS Fig. 1 shows a part of a rock drilling machine 1 including a percussion device with a percussion piston 2. A valve for adjusting the pressure medium for driving the percussion piston is denoted by 5.

Furthermore, a central process unit 6 and a rotation unit, a damping unit etc. are included, which are not shown in Fig. 1. The percussion piston 2 is reciprocable in a machine housing 3.

In the engine housing 3 there are in the area of an impact piston boom 8 a number of guide channels 10 - 13, which are arranged to cooperate with their channel mouths with a first edge 14 of the impact piston boom 8. Indicated by a dashed line at 14 ', a position for the the first edge 14 when the percussion piston has returned after a stroke so that the mouth of the guide channel 10 is uncovered.

A pressurizable chamber 4 accommodates in a manner known per se a drive surface on the percussion piston in the form of a drive flank for a percussion piston boom.

For selected communication between the various control channels and a signal line 15, which leads to the valve 5 for adjusting the direction of movement of the percussion device, a valve member 16 is provided, the function of which is explained below.

The percussion piston 2 is actuated by high fluid pressure in the chamber 4 against a stroke position to initiate a stroke in the direction of the right, as seen in the figure, in a manner known per se, against a drill neck. In the repulsion chamber 9, which occupies a flank of the percussion piston boom, the surface of which is smaller than the surface of the flank in the chamber 4, there is in operation, in a manner known per se, in repulsion of the percussion piston the high pressure. 4, by converting the valve 5, is drained to a tank, the impact piston 2 is then driven back so that after one stroke it is moved in the direction to the left, as seen in Fig. 1, to a position where the guide edge 14 is in the shown position 14 ', as an example. In this case, the higher pressure in the chamber 9 will be transmitted via one of the control channels 10 - 13, which is selected, to the signal line 15, for switching the valve 5 to the left, as seen in the figure, in order to transmit high pressure to the chamber 4. and thus the initiation of a new kind.

Fig. 2 shows the valve member 16 according to a first embodiment, wherein two concentric valve elements control how the control channels 10 - 13 communicate with the signal line 15.

The valve means 16 comprises a first valve element 17 and a second valve element 18 arranged concentrically inside it.

Both valve elements are of cylindrical main configuration and are movable in the axial direction in a selectable manner. A valve housing 19, which receives the valve elements, has on its right end end a constant pressure chamber 20, in which there is a pressure Pd, on both valve elements, which are thus pressed by this pressure to the left as seen in Fig. 2.

The first valve element 17 has on its opposite, left, side a first control chamber 21, which is selectively fed with a pressure P1 which is of such magnitude that pressurization of the first control chamber 21 moves the first valve element from the position shown to a position of Right. A second control chamber 22 is arranged to be selectively pressurized with a second pressure P2, which is able to press the second valve element 18 to the right. In this exemplary embodiment, this means abutment against an inwardly directed shoulder 23 on the first valve element 17. Other solutions with completely independent first and second valve elements are within the scope of the invention.

When the drive chamber <'~ 10 15 20 25 30 530 524 In Figs. 3a to 3d, the function of the valve in Fig. 2 is explained in more detail.

The valve means 16 is shown in Fig. 3a in a position when the "channel" located at the top is alone in connection with the signal line 15, which it is constantly through a permanent connection. Other control channels 10 - 12 are blocked.

It should be emphasized here that the term open in this context means that channel portions of a connection between the control channel and the respective control channels are opened for the possibility of fluid transmission. However, it is not excluded that a control channel, which has a channel portion open, can be part of a connection which, to its extent, is totally blocked by the action of a second valve element.

In Fig. 3a the first valve element 17 is shown in its first position, wherein first portions F1 of connections between a first subset, 10 and 12, of the control channels and the control valve 5 are blocked, this first valve element 17. The second valve element 18 is shown in its first position, wherein a second portion F2 of a connection between a second subset, 10 (/ 11) of the control channels and the control valve 5 is blocked.

In the embodiment in Fig. 3a, the first valve element is designed so that a portion F3 of a connection between the control valve and a control channel 11 from the second subset is open. However, the position of the second valve element blocks the further connection with the control valve 5.

A channel 26 formed by a turn-off in the second valve element and the inner surface of the first valve element together with the upper parts of the channels 24 and 25 constitute in the case of open connection said second portion F2. The control channels 10 - 13 are axially separated by the same pitch and the distance between the channel portions 24 and 25 in the first valve element (approximately) corresponds to the distance 2xL, wherein in this embodiment L the center distance is between two adjacent 10 15 20 25 30 530 524 control channels. It should be noted that a differently constructed "embodiment" can be designed with varying distances between the mouths of the different control channels in order to achieve the desired characteristics of the percussion.

Reference numerals 24 'and 25' refer to circumferential turns in the cylindrical outer wall of the first valve element in a manner known per se for valve bodies of a similar type. The recess 25 'has an axial extent which (approximately) corresponds to L for reasons which will appear below.

The second valve element 18 has two piston portions 27 and 28 sealing against an inner cylindrical space in the first valve element 17 and the intermediate recess 26 has a width exceeding 2xL. It should be noted that the ductwork from the guide channels can be such that the mutual distance between ports in the valve member 16 deviates from the distances between the ports in the cylinder of the percussion piston.

In Fig. 3b, the first valve element 17 is switched to a second position, in which the channel portions 24 and 25 are in open communication with the control channels 10 and 12, the control channel 11 is blocked and the turn-off 25 'mediates fluid contact by open connection with each of the control channels 12 and 13.

Parties F1 are open.

The second valve element 18 is still in its first position and blocks through its piston portion 27 the channel portion 24. In the position shown, both the control channels 12 and 13 thus have fluid contact with the signal line 15. The second portion F2 is blocked.

In Fig. 3c the first valve element 17 is shown in the first position, the same as in Fig. 3a, while the second valve element 18 is in a second position with its axial end, located against the drill neck not shown, in contact with the inwardly directed shoulder 23 in the first valve element. The consequence of this is that the control channel 11 via channel channel 24 530 524 the portion 24, the turn-off 26 and the channel portion 25 has fluid contact with the control channel 13 and thus with the signal line 15.

Said second portion F2 is open.

In Fig. 3d, the first valve element 17 is located in its second position, the same as in Fig. 3b, while the second valve element 18 is also in its second position with abutment against the inwardly directed shoulder 23. The consequence of this is that the control channel 10 has fluid communication with the control channel 13 and thus the signal line 15 via the channel portions 24 and 25 together with the recirculations 26 and 25 '. Lots F1 and F2 are open.

Figs. 4a - 4d show an alternative embodiment of the present invention, wherein in a valve member 16 'three valve bodies 30 - 32 are arranged to control the opening and the blocking, respectively, of their respective control channel. Even in this embodiment, only two control pressures are required for their control.

Due to a first control pressure P1 in the control chambers 30 'and 32', both valve elements 30 and 32 are in their first positions, whereby the connecting portion F1 (through the valve element 30) is blocked and thus between both control channels 10 and 12 and the control valve. Due to a second control pressure P2 in the control chamber 31 ', the valve element 31 is in its first position, whereby the connecting portion F2 between resp. control channels and the control valve and thus the control channel 11 (and also the control channel 10), as shown in Fig. 4a.

By adjusting the control pressure so that in the control chamber 30 'there is a lower pressure P0, an open connection is provided with both control channel 10 and 12. The connecting portion F1 is open, but because the second control pressure P2 prevails in the control chamber 31, the connecting portion F2 and thus the connection is blocked. between the control valve and the control channel 11 (and also the control channel 10), as shown in Fig. 4b.

Because the first control pressure P1 prevails in the control chambers 30 'and 32', both control channel 10 and 12 are blocked and because a lower pressure PG prevails in the control chamber 31 'to provide an open connection with the control channel 11, as can be seen from Fig. 4c.

The connecting section F2 is open.

Because the lower pressure P0 prevails in all control chambers 30 ', 31' and 32 ', the connecting portions F1 and F2 are open. In addition, a connecting portion F4 between the upper part of the guide channel 10 and the portion F3 is open. Thus, provide an open connection with all control channels 10 - 12, as shown in Fig. 4d.

Additional different valve designs may be considered for achieving the desired function.

In total, the longest stroke of the percussion piston is obtained if all control channels 10, 11 and 12 are blocked so that only the control channel 13 communicates with the signal line 15, the valve 5 being switched at a late stage of the re-movement of the percussion piston. The shortest stroke is obtained if the control channel 10 communicates with the signal line 15, whereby the valve 5 is switched at an early stage of the return piston movement.

Fig. 5 indicates a method sequence for effecting strokes in a percussion instrument, wherein: Position 40 indicates the start of the sequence.

Position 41 indicates the generation of a blow in a percussion instrument.

Position 42 indicates the receipt of a parameter signal regarding a parameter describing the drilling process such as the pressure in a damping chamber.

Position 43 indicates analysis of the signal obtained in position 42 and generation of a signal for adjusting valve elements accordingly for modifying the stroke of the piston.

Position 44 indicates the generation of a stroke in the percussion instrument with the modified stroke length.

Position 45 indicates the end of the sequence. The invention may be further modified within the scope of the appended claims.

The percussion device can work according to different principles in addition to what is shown in Fig. 1, with permanently applied pressure in the direction of impact of the percussion piston and alternating pressurization for the return stroke or vice versa.

The invention can be applied in controlling the upper as well as its lower turning position of the percussion piston. It can also be applied to applications without a rotary unit and damper, e.g. called skewers. at so

Claims (20)

10 15 25 30 530 524 ll Patent claims: Percussion device comprising a reciprocating piston (2) reciprocating in a machine housing (3), the movement of which is controllable by a control valve (5), which is arranged to transmit a signal alternately to a pressure depending on the axial position of the percussion piston. source and to low pressure connect a chamber in which a drive surface of the percussion piston (2) is located, a plurality of axially spaced control channels (10, 11, 12, 13) for transmitting said signal having orifices in a percussion piston (2) receiving cylinder space for co-operation with a guide edge (14) on the percussion piston, and wherein valve means (16) are arranged to enable adjustment of in which axial position of the percussion piston said signal is transmitted by opening and blocking the connection between one or more of said control channels (10, 11, 13, 13) and the control valve, characterized in that - said valve means (16) comprises a first valve element (17; 30), which is controllable between a first position, in which it is arranged to block a first portion or portions of a respective connection between a first subset (12; 10) of the control channels and the control valve (5) and a second position, in which it is arranged to open said first portion or portions, and - said valve means (16) also comprises a second valve element (18; 31), which is controllable between a first position, in which it is arranged to block a second portion or portions of a respective connection between a second subset (10, 11) of the control channels and the control valve (5) and a second position, in which it is arranged to open said second portion or portions. 10 15 2O 530 524 l2 Percussion instrument according to claim 1, characterized in that the first subset of control channels comprises one control channel or two control channels. Percussion instrument according to Claim 1 or 2, characterized in that the second subset of control channels comprises one control channel or two control channels. Percussion device according to one of the preceding claims, characterized in that in the second position of the second valve element (18), the first valve element (17) in the first position is arranged to open a connecting portion (F1) between a guide channel (10) and the guide valve. the valve (5) and in the second position is arranged to open a connecting portion (F3) between another control channel (11) and the control valve (5). Percussion device according to one of the preceding claims, characterized in that the valve elements (17, 18) are circular-cylindrical. Percussion device according to claim 5, characterized in that the second valve element (18) is arranged concentrically inside the first valve element (17) and has recesses (26) which cooperate with channel portions (24, extending radially through the material in the first valve element, 25) for opening resp. blocking of said connecting portions. Percussion device according to one of the preceding claims, characterized in that it comprises a third valve element (32) which is controllable simultaneously with the first valve element (30) between a first position, in which it is arranged to block a connecting portion ( F4) between the control valve and a set of control channels and a second position, in which it is arranged to open said connecting portion (F4). Uï 10 15 20 30 530 524 13 Percussion device according to one of the preceding claims, characterized in that an upper guide channel (13), located axially most in one direction from the direction of impact, is constantly connected (15) to the control valve. Percussion device according to claim 8, characterized in that control channels (10, 11, 12), for which connections are arranged to be opened by the valve elements (17, 18; 30, 31, 32), are arranged to be connected to the upper control channel. Percussion device according to one of the preceding claims, characterized in that the valve elements are adjustable by the action of pressure fluid. 11. ll. Percussion device according to one of the preceding claims, characterized in that said valve elements are adjustable in response to a parameter describing the drilling process. Percussion device according to claim 15, characterized in that said parameter is one of the group: drilling subsidence, pressure in a steam chamber, known shock wave amplitude. Rock drilling machine including a percussion device according to any one of claims 1 e 2. A method for controlling a percussion device comprising a reciprocating percussion piston (2) in a machine housing (3), the movement of which is controlled by a control valve (5), which, depending on the axial position of the percussion piston, transmits alternately to a pressure call and to a low pressure, a chamber is connected, in which a driving surface of the percussion piston (2) is located, a plurality of axially spaced control channels (l0.11, l2, l3) for transmitting said signal having orifices in a percussion piston (2) up taking cylinder space for co-operation with a guide edge (14) of the percussion piston, and wherein valve means (16) are arranged to enable adjustment of in which axial position of the percussion said signal is transmitted by opening and blocking the connection, respectively. between one or more of said control channels (10, 11, 12, 13) and the control valve, characterized in that said valve means (16) comprises a first valve element (17:30), which is controlled between a first position, in which it blocks a first portion or portions (F2) of a respective connection between a first subset (12; 10) of the control channels and the control valve (5) and a second position, in which it opens said first portion or portions, and - said valve means (16 ) also comprises a second valve element (18; 31), which is controlled between a first position, in which it blocks a second portion or portions (P2) of a respective connection between a second subset (10, 11) of the guide members. and the control valve (5) and a second position in which it opens said second portion or portions. 15. l5. Method according to claim 14, characterized in that in the second position of the second valve element (18), the first valve element (17) in the first position opens a connecting portion (F1) between a control channel (10) and the control valve (5) and in the the second team opens a connecting portion (F3) between another control channel (II) and the control valve (5). 16. l6. Method according to claim 14 or 15, characterized in that the percussion comprises a third valve element (32) which is controlled simultaneously with the first valve element (30) between a first position, in which it blocks a connecting portion (P4) between the control valve and a set of control channels (10 ) and a second layer, in which it opens said connecting portion (F4). 10 15 530 524 15 Method according to one of Claims 14 to 16, characterized in that guide channels (10, 11, 12), for which connections are opened by the valve elements (17, 18; 30, 31, 32), are connected to an upper guide channel. Method according to one of Claims 14 to 17, characterized in that the valve elements are converted by the application of pressure fluid. Method according to any one of claims 14 - 18, characterized in that said valve element is adjusted in response to a parameter describing a drilling process. Method according to claim 19, characterized in that said parameters are one of the group: drilling subsidence, pressure in a damping chamber, sensed shock wave amplitude.